VERDER CARBOLITE GERO BLF 18/8 Manual

Installation, Operation and Maintenance Instructions
1800°C Bottom Loading Furnace - BLF Model: 8 Litres
No Controller
BLF 18/8 + No Controller
MEN-BLF1808-003_NOCTRL (29-10-2021)

Contents
This manual is for guidance on the use of the Carbolite Gero product specified on the
front cover. This manual should be read thoroughly before unpacking and using the
furnace or oven. The model details and serial number are shown on the back of this
manual. Use the product for the purpose for which it is intended.
1.0 Symbols and Warnings 4
1.1 Switches and Lights 4
1.2 General Warnings 4
1.3 Prerequisites to Use 5
2.0 Installation 6
2.1 Unpacking and Handling 6
2.2 Siting and Setting Up 6
2.3 Fitting the Chimney and Heating Elements 7
2.4 Electrical Connections 8
3.0 Temperature Controller 10
4.0 Operation 11
4.1 Operating Cycle 11
4.2 Emergency Stop Button 11
4.3 General Operating Advice 11
4.4 Atmospheres & Corrosive Materials 12
4.5 Operator Safety 13
4.6 Notes on Temperature Control 13
4.7 Insulation Cracking 13
4.8 Thermocouple Warnings 13
4.9 Inverted Crucible Option 14
4.10 Element Protection Tube Option 14
5.0 Maintenance 15
5.1 General Maintenance 15
5.2 Maintenance Schedule 15
5.2.1 Cleaning 17
5.3 Calibration 17
5.4 After-Sales Service 17
5.5 Recommended Spare Parts and Spare Parts Kit 17
5.6 Power Adjustment (Controller) 17
5.7 Power Adjustment (Thyristor) 18
6.0 Repairs and Replacements 19
6.1 Safety Warning - Disconnection from Power Supply 19
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6.2 Safety Warning - Refractory Fibre Insulation 19
6.3 Safety Warning - Molybdenum Disilicide Elements 20
6.4 Temperature Controller Replacement 20
6.5 Fuse Replacement 20
6.6 Thermocouple Replacement 20
6.7 Element Protection Tube Option Replacement Procedure 21
6.8 Insulation Replacement 21
6.9 Element Installation and Replacement 22
7.0 Fault Analysis 25
A. Furnace Does Not Heat Up 25
B. Product Overheats 26
8.0 Wiring Diagrams 27
8.1 215-1-1009 27
8.2 215-1-1007 28
9.0 Fuses and Power Settings 29
9.1 Fuses 29
9.2 Power Settings 29
10.0 Specifications 30
10.1 Environment 30
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1.0 Symbols and Warnings
1.1 Switches and Lights
Instrument switch: when the instrument switch is operated the
temperature control circuit is energised.
Heat light: the adjacent light glows or flashes to indicate that
power is being supplied to the elements.
1.2 General Warnings
DANGER – Electric shock. Read any warning printed next to this
symbol.
WARNING: Risk of fatal injury.
DANGER – Hot surface. Read any warning printed next to this
symbol.
WARNING: All surfaces of a product may be hot.
DANGER – Read any warning printed next to this symbol.
Caution – Double Pole/Neutral Fusing
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1.3 Prerequisites to Use
Prior to the commissioning and use of this product, all personnel involved in its
installation, operation and maintenance must be deemed competent and have:
lRead and understood the information contained within this manual
lReceived the relevant training with regard to safety and operation of the product
lBeen provided with the appropriate PPE (Personal Protective Equipment) required
for the safe operation of this product
Note: The customer is responsible for ensuring that all of the above conditions are
satisfied before the product is commissioned for use.
Note: Unless otherwise specified, the customer is responsible for the
installation of this product and the safe connection of any additional
equipment and gas or liquid supply lines.
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2.0 Installation
2.1 Unpacking and Handling
When unpacking or moving the product always lift it by its base. Do not use the door or
any other protruding parts. The product contains a transformer and is heavy: use two
or more people to carry the product.
Some models may alternatively be lifted by fitting lifting bolts to captive threads in the
top of the case.
Remove any packing material.
NOTE: This product contains Refractory Ceramic Fibre (also known
as Alumino Silicate Wool - ASW). For precautions and advice on
handling this material see section 6.2.
2.2 Siting and Setting Up
Place the product on a level surface in a well ventilated area.
Site away from other sources of heat and on a non-flammable surface that is resistant
to accidental spillage or hot materials.
The surface on which the equipment is mounted should be stable and not subject to
movement or vibrations.
The height of the mounting surface is important to avoid operator strain when loading
and unloading samples.
Unless otherwise stated elsewhere in this manual, ensure that there is at least 150
mm of free space around the back and sides of the product. Clear space is required
above the product to dissipate heat.
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Depending on the application of the product, it may be appropriate to position it under
an extraction hood. Ensure the extraction hood is switched on during use.
Ensure that the product is placed in such a way that it can be quickly switched off or
disconnected from the electrical supply.
Under no circumstances should any objects be placed on top of the
product. Always ensure that any vents on the top of the product are clear
of any obstruction. Always ensure all cooling vents and cooling fans (if
fitted) are clear of any obstruction.
2.3 Fitting the Chimney and Heating Elements
Please refer to the Element Installation and Replacement in section
6.0. Wear eye protection when handling the heating elements.
The molybdenum disilicide elements are EXCEPTIONALLY FRAGILE
and are packed separately, together with other items shown in the
list.
separately packed items BLF
Elements 9
Element Clamps 18
Elements Clips* 18
Braids* 1 set
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separately packed items BLF
Separators 9
* or combined clips and braids may be supplied
Transit Clamps – dependent
on model: the example shown
here is for the 3 litre models;
remove any transit clamps as
shown. Fit the ceramic
chimney to the hole that exits
the top of the chamber. Most
models are supplied with an
insulation piece to fit around
the chimney; fit this
insulation.
Remove the complete top
access panel using the hidden
screw in holes in the top of
the panel; loosen the screws
two turns and remove the
panel.
Fit the heating elements
vertically into the chamber.
Handle the elements with
great care.
Connect the aluminium braids
securely as indicated in the
element installation
instructions.
2.4 Electrical Connections
Connection by a qualified electrician is recommended.
This model is designed for connection to a three phase power supply. This may be with
neutral or delta, but a product must only be connected to the type and voltage of
supply for which it was made.
Check the product rating label before connection. The supply voltage should agree with
the voltage on the label and the supply capacity should be sufficient for the current on
the label.
The supply should be fused at the next size equal to, or higher than the current on the
label. This manual contains a table of the most common fuse ratings.
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When the mains cable is factory fitted, internal fuses are also fitted. It is essential that
the operator ensures that the product is correctly fused.
Products with a factory fitted supply cable are designed to be wired directly to an
isolator or fitted with a line plug.
Products without a factory fitted supply cable require a permanent connection to a
fused and isolated supply. The product's electrical access panel should be temporarily
removed, and connections made to the internal terminals.
When connecting the product to the power supply, the plug or isolating switch should
be accessible, easy to remove, and within reach of the operator.
The supply MUST incorporate an earth (ground).
Supply Terminal Label Cable Colour Supply Type
3-phase L1 Black to phase 1
L2 Black to phase 2
L3 Black to phase 3
N Light Blue to neutral (except delta)
PE Green/ Yellow to earth (ground)
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3.0 Temperature Controller
If this product is fitted with a temperature controller, instructions are provided
separately.
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4.0 Operation
4.1 Operating Cycle
This product is fitted with an instrument switch which cuts off power to the control
circuit.
Connect the product to the electrical supply.
The cooling fans should automatically operate.
The furnace is fitted with a pair of gates that have a safety switch. the hearth can only
be lowered or raised if the gates are closed. The furnace is also fitted with a radiation
shield. The hearth can only be raised or lowered if this is in the open position.
Check the hearth control switch for correct operation. The spring return switch stops
the hearth in any position, but over-travel is automatically limited. Load the furnace
and raise the hearth.
Turn on the instrument switch to activate the temperature controllers. The controllers
illuminate and go through a short test cycle.
Set the over-temperature controller to a temperature a little (e.g. 15 °C) above the
maximum setpoint of program temperature, according to the instructions supplied.
The product will heat up according to the controller setpoint or program, unless a time
switch is fitted and switched off. The heat light glows brightly at first, more dimly as
the product temperature approaches a program setpoint.
Over-Temperature option only. If the over-temperature circuit has tripped, an
indicator on the over-temperature controller flashes and the heating elements are
isolated. Find and correct the cause before resetting the over-temperature controller
according to the instructions supplied.
To switch the furnace off, set the instrument switch to off. The case cooling fans
remain on and the chamber can be unloaded. Leave the fans on until the product cools
to below 300 °C. If the product is to be left off unattended, isolate it from the electrical
supply.
4.2 Emergency Stop Button
Pushing the emergency stop button will stop the hearth from moving and prevent the
elements from heating.
Once the button has been pushed, twist the emergency stop button to reset.
4.3 General Operating Advice
Heating element life is shortened by overheating. Do not leave the
product at high temperature when it is not required. The maximum
temperature is shown on the product rating label and in section 10.0
towards the back of this manual.
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When heating large objects, in particular poor conductors, avoid shielding the
thermocouple from the heating elements. The thermocouple is intended to sense the
temperature near the heating elements. However, if a large object is placed in the
chamber it may record the average temperature of the object and the elements, this
can lead to overheating of the elements. Allow large objects to gain heat at a lower
temperature and then reset the controller to a temperature close to the desired
maximum, or heat using a slowly controlled ramp rate. For more information refer to
the controller instructions.
The product's elements are very susceptible to mechanical shock. Take great care when
loading or unloading the chamber. If it is necessary to load or unload work at elevated
temperatures, keep the door open for as short a period as possible. The insulation cools
quickly and may crack though thermal shock.
For improved insulation and element life it is recommended to heat and cool at a slow
ramp rate e.g. 5 °C/minute, and to avoid opening the door at high temperatures.
On first installing the elements and on subsequent element replacement, operate the
product at 1500 °C for an hour to create a protective glaze on the element surface.
4.4 Atmospheres & Corrosive Materials
In oxidising atmospheres, metal oxides react with the silica layer on the surface of the
elements and may lead to premature failure. Protect the elements from splashes of
molten metal and dust when loading the furnace and from fumes developed when
melting, especially from fluxes. Also avoid compounds with a high alkali content.
The furnace is designed for use up to its maximum temperature in oxidising
atmospheres, but can be operated successfully in neutral or carburising atmospheres. It
may be used with nitrogen, argon or helium atmospheres to 1600 °C. Reducing
atmospheres are not recommended. Sulphur dioxide is not harmful in low
concentrations. However chlorine and fluorine attacks oxidised elements and should be
avoided. A harmful gas is produced and collects in poorly ventilated spaces.
The furnace is not recommended for burning off carbonaceous materials. Other
Carbolite Gero furnaces are available for this application.
When an optional gas inlet is fitted there is a label near the inlet saying "INERT GAS
ONLY".
The chamber is not gas tight, the gas usage may be high and the chamber is always
likely to contain some air. Residual oxygen of approximately 1% to 2% is to be
expected.
Periodically operate the furnace in air at 1500 °C for an hour to ensure the protective
glaze on the elements surface is maintained.
The hearth can be protected from abrasion, if required, by the provision of a secondary
plate. This consumable item can either be in lightweight ceramic fibre or in dense,
hard-wearing alumina refractory.
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4.5 Operator Safety
This product incorporates a safety switch which interrupts the
heating element circuit when the furnace is opened. This prevents
the operator touching a live heating element and also prevents the
product from heating up if the furnace is left open. The operation of
this switch should be checked periodically.
Depending on use, the surfaces in the working chamber and the
chamber load may still be very hot after the appliance is switched
off. Touching these surfaces may cause burns. Use suitable personal
protective equipment or wait until the appliance cools down to
ambient temperature.
Before removing a hot object from the product, make sure there is a safe place to put
it down. If necessary use tongs, face masks and heat resistant gloves. Heat resistant
clothing and face protection can guard against the effects of radiated heat when the
furnace is open.
When the product is opened during operation there is considerable radiated heat. Do
not keep any flammable objects near the product, nor objects which could be damaged
by radiated heat.
4.6 Notes on Temperature Control
This product is designed for heating and cooling at controlled rates. The heating and
cooling rates can be set in the temperature programmer. The programmer enables the
furnace to heat or cool at slower rates as desired and variable "hold" (dwell) periods
can be programmed as required.
The programmer is used in conjunction with a phase angle thyristor power controller,
which incorporates a current limit potentiometer pre-set by Carbolite Gero, but which
will require adjustment in the event of change of supply voltage.
The elements are connected in series across the low voltage output of a transformer
housed in the furnace case. Molybdenum disilicide elements do not age, if an element
fails it is not necessary to replace the complete set.
4.7 Insulation Cracking
The insulation material in this furnace is susceptible to surface cracking as a result of
temperature cycling. This is a normal occurrence and such cracking is not detrimental
to the performance of the overall life of the furnace, under normal operation.
4.8 Thermocouple Warnings
(1) The output from 1700-1800 °C thermocouples when used regularly at
temperatures greater than 1650 °C can deteriorate and decrease with age faster than
if used at temperatures below 1650 °C; this will cause the furnace to operate at
temperatures higher than indicated.
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Operators are advised to periodically check the thermocouple output, either by a
calibration test or by comparing the output with a new reference thermocouple which
has been subjected to high temperatures for a minimum length of time.
Failure to check the thermocouple regularly may result in overheating of the work and
the furnace, with consequential damage to both.
(2) The thermocouples fitted to these models give very low outputs below
approximately 600 °C and do not give accurate readings at low temperatures. They
may show a negative temperature when the furnace is started from cold.
This furnace is not intended to operate with a setpoint below 600 °C.
4.9 Inverted Crucible Option
Take special care over safety considerations: ensure that there is a safe surface on
which to place the crucible when hot. If the process permits, avoid lowering the hearth
when the chamber is hot.
Depending on the height of the work-piece, it may be necessary to hold the crucible up
in the chamber when placing the work-piece on the hearth; ensure that appropriate
tongs are available before starting.
Clamp Option
This option assists the placing of the crucible over tall work-pieces. The “clamp” is
provided in the form of a support shelf which can be fitted to a hinge on the case and a
pair of insulated tongs.
With the hearth lowered, place the support shelf on the hinge and swing to the side.
Use the tongs to lift the crucible up into the chamber, swing the shelf to the centre and
lower the crucible.
Place the work-piece. Reverse the procedure above and carefully lower the crucible
over the work-piece. Remove the shelf before raising the hearth.
4.10 Element Protection Tube Option
For application where the material being heated may give off fumes or splash, an
inverted crucible can be fitted to protect the elements that is permanently located in
the furnace body.
The tubes utilised for element protection within the BLF range of furnaces are fragile
and extreme care should be taken when handling them.
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5.0 Maintenance
5.1 General Maintenance
Preventive rather than reactive maintenance is recommended. The type and frequency
depends on the product use; the following are recommended.
5.2 Maintenance Schedule
CUSTOMER
QUALIFIED PERSONNEL
DANGER! ELECTRIC SHOCK. Risk of fatal injury. Only electrically
qualified personnel should attempt these maintenance procedures.
Maintenance
Procedure Method
Frequency
Daily Weekly Monthly Bi-
Annually Annually
Safety
Safety Switch Function
Set a safe temperature above ambient, and
lower the hearth to see if the heater light
goes out
Safety Switch Function
While lowering or raising the hearth operate
the emergency stop button to prove that it
functions correctly.
Safety Switch Function Check that the hearth will not raise or lower
with the cage open.
Safety Switch Function Electrical measurement
Over-Temperature Safety
Circuit
(if fitted)
Set an over-temperature setpoint lower
than the current displayed temperature and
check for an over-temperature alarm as
detailed in this manual
Over-Temperature Safety
Circuit
(if fitted) Electrical measurement
Hearth Visual inspection, checking the seal and
whether it is free of damage
Hearth Replacement where necessary
Cooling Fans (if fitted) Check whether the cooling fans are working
Chimney / Extraction Check and clean if necessary
Electrical Safety
(external) Visual check of external cables and plugs
Electrical Safety (internal) Physically check all connections and clean-
ing of the power plate area
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Function
Temperature Calibration Tested using certified equipment, frequency
dependent on the standard required
Operational Check Check that all functions are working nor-
mally
Operational Check Thorough inspection and report incor-
porating a test of all functions
Performance
Element Circuit Electrical measurement
Power Consumption Measure the current drawn on each phase /
circuit
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5.2.1 Cleaning
Soot deposits may form inside the furnace, depending on the process. At appropriate
intervals remove these by heating as indicated in the General Operation Notes.
The product's outer surface may be cleaned with a damp cloth. Do
not allow water to enter the interior of the case or chamber. Do not
clean with organic solvents.
5.3 Calibration
After prolonged use, the controller and/or thermocouple may require recalibration. This
is important for processes that require accurate temperature readings or for those that
use the product close to its maximum temperature. A quick check using an
independent thermocouple and temperature indicator should be made from time to
time to determine whether full calibration is required. Carbolite Gero can supply these
items.
Depending on the controller fitted, the controller instructions may contain calibration
instructions.
5.4 After-Sales Service
Carbolite Gero Service has a team of Service Engineers who can offer repair, calibration
and preventive maintenance of furnace and oven products both at the Carbolite Gero
factory and at customers’ premises throughout the world. A telephone call or email
often enables a fault to be diagnosed and the necessary parts to be despatched.
In all correspondence please quote the serial number and model type given on the
rating label of the product. The serial number and model type are also given on the
back of this manual when supplied with the product.
Carbolite Gero Service and Carbolite Gero contact information can be found on the
back page of this manual.
5.5 Recommended Spare Parts and Spare Parts Kit
Carbolite Gero can supply individual spare parts or a kit of the items most likely to be
required. Ordering a kit in advance can save time in the event of a breakdown.
Each kit consists of one thermocouple, one sheath, one power thyristor, one door
insulation piece and a set of elements, clips and braids, element clamps and insulators.
Individual spare parts are also available.
When ordering spare parts please quote the model details as requested above.
5.6 Power Adjustment (Controller)
The product's controller incorporates a power limit parameter OP.Hi, which is usually
inaccessible to the operator.
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The correct setting for the power limit depends on the supply voltage, table given in
section9.0
5.7 Power Adjustment (Thyristor)
The current-limiting thyristor stacks which control power to the elements are fitted with
an adjustable resistor which is factory set to limit the maximum current supplied. In the
event of a change of supply voltage, or the fitting of a new thyristor, further adjustment
may be required.
The maximum element currents for this model are listed in section 9.0. Please contact
Carbolite Gero for further information.
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6.0 Repairs and Replacements
6.1 Safety Warning - Disconnection from Power Supply
Immediately switch the product off in the event of unforeseen
circumstances (e.g. large amount of smoke). Allow the product to
return to room temperature before inspection.
Always ensure that the product is disconnected from the electrical
supply before repair work is carried out.
Caution: Double pole/neutral fusing may be used in this product.
6.2 Safety Warning - Refractory Fibre Insulation
Insulation made from High Temperature Insulation Wool
Refractory Ceramic Fibre, better known as (Alumina silicate
wool - ASW).
This product contains alumino silicate wool products in its thermal insulation. These
materials may be in the form of blanket or felt, formed board or shapes, slab or loose
fill wool.
Typical use does not result in any significant level of airborne dust from these
materials, but much higher levels may be encountered during maintenance or repair.
Whilst there is no evidence of any long term health hazards, it is strongly
recommended that safety precautions are taken whenever the materials are handled.
Exposure to fibre dust may cause respiratory disease.
When handling the material, always use approved respiratory protection
equipment (RPE-eg. FFP3), eye protection, gloves and long sleeved clothing.
Avoid breaking up waste material. Dispose of waste in sealed containers.
After handling, rinse exposed skin with water before washing gently with
soap (not detergent). Wash work clothing separately.
Before commencing any major repairs it is recommended to make reference to the
European Association representing the High Temperature Insulation Wool industry
(www.ecfia.eu).
Further information can be provided on request. Alternatively, Carbolite Gero Service
can quote for any repairs to be carried out either on site or at the Carbolite Gero
factory.
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6.3 Safety Warning - Molybdenum Disilicide Elements
Molybdenum disilicide elements form a glazed surface when heated.
Internal stresses can form through heating and cooling which render
the glaze fragile. The glaze can sometimes splinter into a shower of
sharp particles when handled. Always wear eye protection when
handling the elements.
Handle the heating elements with extreme care as they are very fragile. Also, avoid
touching the heating surface (the thin part of the element), as the material is
susceptible to corrosive damage from skin contact.
6.4 Temperature Controller Replacement
Refer to the controller instructions for more information on how to replace the
temperature controller.
6.5 Fuse Replacement
Fuses are marked on the wiring diagram with type codes, e.g. F1, F2. For more
information on fuses refer to section 9.0.
Depending on model and voltage, the different fuse types may or may not be fitted.
If any fuse has failed, it is advisable for an electrician to check the internal circuits.
Replace any failed fuses with the correct type. For safety reasons do not fit larger
capacity fuses without first consulting Carbolite Gero.
The fuses are located at the cable entry point. Remove the back panel or control box
back panel to gain access to the fuses.
6.6 Thermocouple Replacement
Disconnect the product from the electrical supply and remove the product's element
access panel.
Make a note of the thermocouple connections. The negative leg of the thermocouple
is marked blue. The "compensating" cable for 1700 & 1800 °C thermocouples is plain
copper.
Disconnect the thermocouple from its terminal block.
Bend the metal, or release the thermocouple sheath; withdraw the sheath and shake
out any fragments of thermocouple.
Re-assemble with a new thermocouple observing the colour coding. Ensure that the
thermocouple is not twisted as it is being inserted and that the metal tag is bent back,
or the screw inserted, to grip the sheath.
Refit the product's element access panel.
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